1. Field
The following description relates to methods and apparatuses for recording micro-holograms.
2. Description of the Related Art
Holography is a technology involving an interference pattern caused by a signal beam containing a signal beam and a reference beam. The interference pattern is recorded to reproduce the signal as a stereoscopic image. Holography may be used in fields such as recordation and reproduction of stereoscopic images, prevention of forgery and verification of genuine articles, and recordation and reproduction of digital data. In addition, fine interference patterns may be recorded on a flat photosensitive recording film. The recording of the fine interference patterns may be in units of pixels, so that a three-dimensional image may be viewed on a two-dimensional plane.
Micro-holograms may be classified as a rear projection micro-hologram or a reflective micro-hologram. The rear projection micro-hologram may relate to a stereoscopic image contained in light that has been transmitted through a recording film, and the reflective micro-hologram may relate to a stereoscopic image contained in light reflected by a recording film. In another example, the reflective micro-hologram may record and/or reproduce full-color or full-parallax images, and the reflective micro-hologram may represent gradation.
In general, division of a beam emitted from a light source into a signal beam and a reference beam, light-modulation of the signal beam, and irradiation of the signal beam and the reference beam onto the same location on a photosensitive recording film may record image information onto a micro-hologram. Usage of a spatial light-modulator according to an interference pattern calculated by a computer based on an image that is to be finally reproduced from a photosensitive recording film may modulate a signal beam.
In response to recording a micro-hologram, exposure energy applied to a photosensitive recording film may be a significant factor in recording of the micro-hologram. An intensity of light that is irradiated to a photosensitive recording film and exposure time may determine the exposure energy. In order to improve a quality of an image to be reproduced, appropriate amount of exposure energy is to be provided to a photosensitive recording film. In response to an output of laser used as a light source being weak, an exposure time may be increased, and accordingly, a time for recording of a micro-hologram may be increased. In addition, recording of a micro-hologram may be affected by external factors such as vibration. In addition, the manufacturing costs for a micro-hologram recording apparatus may increase, and consumption power may also increase in response to a high output laser being used as the light source.